
/*
** $Id: lua.c,v 1.160 2006/06/02 15:34:00 roberto Exp $
** Lua stand-alone interpreter
** See Copyright Notice in lua.h
*/


#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define lua_c

extern "C" {
#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"
}

#include "osgLua.h"


static lua_State *globalL = NULL;

static const char *progname = LUA_PROGNAME;



static void lstop (lua_State *L, lua_Debug *ar) {
	(void)ar;  /* unused arg. */
	lua_sethook(L, NULL, 0, 0);
	luaL_error(L, "interrupted!");
}


static void laction (int i) {
	signal(i, SIG_DFL); /* if another SIGINT happens before lstop,
						terminate process (default action) */
	lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
}


static void print_usage (void) {
	fprintf(stderr,
		"usage: %s [options] [script [args]].\n"
		"Available options are:\n"
		"  -e stat  execute string " LUA_QL("stat") "\n"
		"  -l name  require library " LUA_QL("name") "\n"
		"  -i       enter interactive mode after executing " LUA_QL("script") "\n"
		"  -v       show version information\n"
		"  --       stop handling options\n"
		"  -        execute stdin and stop handling options\n"
		,
		progname);
	fflush(stderr);
}


static void l_message (const char *pname, const char *msg) {
	if (pname) fprintf(stderr, "%s: ", pname);
	fprintf(stderr, "%s\n", msg);
	fflush(stderr);
}


static int report (lua_State *L, int status) {
	if (status && !lua_isnil(L, -1)) {
		const char *msg = lua_tostring(L, -1);
		if (msg == NULL) msg = "(error object is not a string)";
		l_message(progname, msg);
		lua_pop(L, 1);
	}
	return status;
}


static int traceback (lua_State *L) {
	lua_getfield(L, LUA_GLOBALSINDEX, "debug");
	if (!lua_istable(L, -1)) {
		lua_pop(L, 1);
		return 1;
	}
	lua_getfield(L, -1, "traceback");
	if (!lua_isfunction(L, -1)) {
		lua_pop(L, 2);
		return 1;
	}
	lua_pushvalue(L, 1);  /* pass error message */
	lua_pushinteger(L, 2);  /* skip this function and traceback */
	lua_call(L, 2, 1);  /* call debug.traceback */
	return 1;
}


static int docall (lua_State *L, int narg, int clear) {
	int status;
	int base = lua_gettop(L) - narg;  /* function index */
	lua_pushcfunction(L, traceback);  /* push traceback function */
	lua_insert(L, base);  /* put it under chunk and args */
	signal(SIGINT, laction);
	status = lua_pcall(L, narg, (clear ? 0 : LUA_MULTRET), base);
	signal(SIGINT, SIG_DFL);
	lua_remove(L, base);  /* remove traceback function */
	/* force a complete garbage collection in case of errors */
	if (status != 0) lua_gc(L, LUA_GCCOLLECT, 0);
	return status;
}


static void print_version (void) {
	l_message(NULL, LUA_RELEASE "  " LUA_COPYRIGHT);
}


static int getargs (lua_State *L, char **argv, int n) {
	int narg;
	int i;
	int argc = 0;
	while (argv[argc]) argc++;  /* count total number of arguments */
	narg = argc - (n + 1);  /* number of arguments to the script */
	luaL_checkstack(L, narg + 3, "too many arguments to script");
	for (i=n+1; i < argc; i++)
		lua_pushstring(L, argv[i]);
	lua_createtable(L, narg, n + 1);
	for (i=0; i < argc; i++) {
		lua_pushstring(L, argv[i]);
		lua_rawseti(L, -2, i - n);
	}
	return narg;
}


static int dofile (lua_State *L, const char *name) {
	int status = luaL_loadfile(L, name) || docall(L, 0, 1);
	return report(L, status);
}


static int dostring (lua_State *L, const char *s, const char *name) {
	int status = luaL_loadbuffer(L, s, strlen(s), name) || docall(L, 0, 1);
	return report(L, status);
}


static int dolibrary (lua_State *L, const char *name) {
	lua_getglobal(L, "require");
	lua_pushstring(L, name);
	return report(L, lua_pcall(L, 1, 0, 0));
}


static const char *get_prompt (lua_State *L, int firstline) {
	const char *p;
	lua_getfield(L, LUA_GLOBALSINDEX, firstline ? "_PROMPT" : "_PROMPT2");
	p = lua_tostring(L, -1);
	if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
	lua_pop(L, 1);  /* remove global */
	return p;
}


static int incomplete (lua_State *L, int status) {
	if (status == LUA_ERRSYNTAX) {
		size_t lmsg;
		const char *msg = lua_tolstring(L, -1, &lmsg);
		const char *tp = msg + lmsg - (sizeof(LUA_QL("<eof>")) - 1);
		if (strstr(msg, LUA_QL("<eof>")) == tp) {
			lua_pop(L, 1);
			return 1;
		}
	}
	return 0;  /* else... */
}


static int pushline (lua_State *L, int firstline) {
	char buffer[LUA_MAXINPUT];
	char *b = buffer;
	size_t l;
	const char *prmt = get_prompt(L, firstline);
	if (lua_readline(L, b, prmt) == 0)
		return 0;  /* no input */
	l = strlen(b);
	if (l > 0 && b[l-1] == '\n')  /* line ends with newline? */
		b[l-1] = '\0';  /* remove it */
	if (firstline && b[0] == '=')  /* first line starts with `=' ? */
		lua_pushfstring(L, "return %s", b+1);  /* change it to `return' */
	else
		lua_pushstring(L, b);
	lua_freeline(L, b);
	return 1;
}


static int loadline (lua_State *L) {
	int status;
	lua_settop(L, 0);
	if (!pushline(L, 1))
		return -1;  /* no input */
	for (;;) {  /* repeat until gets a complete line */
		status = luaL_loadbuffer(L, lua_tostring(L, 1), lua_strlen(L, 1), "=stdin");
		if (!incomplete(L, status)) break;  /* cannot try to add lines? */
		if (!pushline(L, 0))  /* no more input? */
			return -1;
		lua_pushliteral(L, "\n");  /* add a new line... */
		lua_insert(L, -2);  /* ...between the two lines */
		lua_concat(L, 3);  /* join them */
	}
	lua_saveline(L, 1);
	lua_remove(L, 1);  /* remove line */
	return status;
}


static void dotty (lua_State *L) {
	int status;
	const char *oldprogname = progname;
	progname = NULL;
	while ((status = loadline(L)) != -1) {
		if (status == 0) status = docall(L, 0, 0);
		report(L, status);
		if (status == 0 && lua_gettop(L) > 0) {  /* any result to print? */
			lua_getglobal(L, "print");
			lua_insert(L, 1);
			if (lua_pcall(L, lua_gettop(L)-1, 0, 0) != 0)
				l_message(progname, lua_pushfstring(L,
				"error calling " LUA_QL("print") " (%s)",
				lua_tostring(L, -1)));
		}
	}
	lua_settop(L, 0);  /* clear stack */
	fputs("\n", stdout);
	fflush(stdout);
	progname = oldprogname;
}


static int handle_script (lua_State *L, char **argv, int n) {
	int status;
	const char *fname;
	int narg = getargs(L, argv, n);  /* collect arguments */
	lua_setglobal(L, "arg");
	fname = argv[n];
	if (strcmp(fname, "-") == 0 && strcmp(argv[n-1], "--") != 0) 
		fname = NULL;  /* stdin */
	status = luaL_loadfile(L, fname);
	lua_insert(L, -(narg+1));
	if (status == 0)
		status = docall(L, narg, 0);
	else
		lua_pop(L, narg);      
	return report(L, status);
}


/* check that argument has no extra characters at the end */
#define notail(x)	{if ((x)[2] != '\0') return -1;}


static int collectargs (char **argv, int *pi, int *pv, int *pe) {
	int i;
	for (i = 1; argv[i] != NULL; i++) {
		if (argv[i][0] != '-')  /* not an option? */
			return i;
		switch (argv[i][1]) {  /* option */
	  case '-':
		  notail(argv[i]);
		  return (argv[i+1] != NULL ? i+1 : 0);
	  case '\0':
		  return i;
	  case 'i':
		  notail(argv[i]);
		  *pi = 1;  /* go through */
	  case 'v':
		  notail(argv[i]);
		  *pv = 1;
		  break;
	  case 'e':
		  *pe = 1;  /* go through */
	  case 'l':
		  if (argv[i][2] == '\0') {
			  i++;
			  if (argv[i] == NULL) return -1;
		  }
		  break;
	  default: return -1;  /* invalid option */
		}
	}
	return 0;
}


static int runargs (lua_State *L, char **argv, int n) {
	int i;
	for (i = 1; i < n; i++) {
		if (argv[i] == NULL) continue;
		lua_assert(argv[i][0] == '-');
		switch (argv[i][1]) {  /* option */
	  case 'e': {
		  const char *chunk = argv[i] + 2;
		  if (*chunk == '\0') chunk = argv[++i];
		  lua_assert(chunk != NULL);
		  if (dostring(L, chunk, "=(command line)") != 0)
			  return 1;
		  break;
				}
	  case 'l': {
		  const char *filename = argv[i] + 2;
		  if (*filename == '\0') filename = argv[++i];
		  lua_assert(filename != NULL);
		  if (dolibrary(L, filename))
			  return 1;  /* stop if file fails */
		  break;
				}
	  default: break;
		}
	}
	return 0;
}


static int handle_luainit (lua_State *L) {
	const char *init = getenv(LUA_INIT);
	if (init == NULL) return 0;  /* status OK */
	else if (init[0] == '@')
		return dofile(L, init+1);
	else
		return dostring(L, init, "=" LUA_INIT);
}


struct Smain {
	int argc;
	char **argv;
	int status;
};


static int pmain (lua_State *L) {
	struct Smain *s = (struct Smain *)lua_touserdata(L, 1);
	char **argv = s->argv;
	int script;
	int has_i = 0, has_v = 0, has_e = 0;
	globalL = L;
	if (argv[0] && argv[0][0]) progname = argv[0];
	lua_gc(L, LUA_GCSTOP, 0);  /* stop collector during initialization */
	luaL_openlibs(L);  /* open libraries */
	luaopen_osgLua(L);
	lua_gc(L, LUA_GCRESTART, 0);
	s->status = handle_luainit(L);
	if (s->status != 0) return 0;
	script = collectargs(argv, &has_i, &has_v, &has_e);
	if (script < 0) {  /* invalid args? */
		print_usage();
		s->status = 1;
		return 0;
	}
	if (has_v) print_version();
	s->status = runargs(L, argv, (script > 0) ? script : s->argc);
	if (s->status != 0) return 0;
	if (script)
		s->status = handle_script(L, argv, script);
	if (s->status != 0) return 0;
	if (has_i)
		dotty(L);
	else if (script == 0 && !has_e && !has_v) {
		if (lua_stdin_is_tty()) {
			print_version();
			dotty(L);
		}
		else dofile(L, NULL);  /* executes stdin as a file */
	}
	return 0;
}


int main (int argc, char **argv) {
	int status;
	struct Smain s;
	lua_State *L = lua_open();  /* create state */
	if (L == NULL) {
		l_message(argv[0], "cannot create state: not enough memory");
		return EXIT_FAILURE;
	}
	s.argc = argc;
	s.argv = argv;
	status = lua_cpcall(L, &pmain, &s);
	report(L, status);
	lua_close(L);
	return (status || s.status) ? EXIT_FAILURE : EXIT_SUCCESS;
}

